/*
 * Copyright (c) 2024 Yunshan Networks
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package grpc

import (
	"fmt"
	"net"

	"github.com/vishvananda/netlink"
)

func Lookup(host net.IP) (net.IP, error) {
	routes, err := netlink.RouteGet(host)
	if err != nil {
		return nil, fmt.Errorf("RouteGet %v %s", host, err)
	}
	route := routes[0]
	src := route.Src
	if route.Src.To4() != nil {
		src = route.Src.To4()
	}
	return src, nil
}
